#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 30

void error_handling(char* message);
// void read_childproc(int sig);
void read_routine(int sock, char* buf);
void write_routine(int sock, char* buf);

int main(int argc, char* argv[])
{
    int sock;
    struct sockaddr_in serv_adr;

    char buf[BUF_SIZE];

    pid_t pid;

    if(argc != 3)
    {
        printf("Usage  %s : <ip> <port> \n", argv[0]);
        exit(1);
    }

    //socket()创建套接字
    sock = socket(PF_INET, SOCK_STREAM, 0);
    if(sock == -1)
        error_handling("socket() error\n");
    
    //connect()服务器
    memset(&serv_adr, 0, sizeof(serv_adr));
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_addr.s_addr = inet_addr(argv[1]);
    serv_adr.sin_port = htons(atoi(argv[2]));

    if(connect(sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr)) == -1)
        error_handling("connect() error\n");
    else
        puts("Connected...");

    pid = fork();
    if(pid == 0)
        write_routine(sock, buf);
    else
        read_routine(sock, buf);

    close(sock);
    return 0;
}

void read_routine(int sock, char* buf)
{
    while(1)
    {
        int str_len = read(sock, buf, BUF_SIZE - 1);
        if(str_len == 0)
            return;
        
        buf[str_len] = 0;
        printf("message from server : %s \n", buf);
    }
}
void write_routine(int sock, char* buf)
{
    while(1)
    {
        fgets(buf, BUF_SIZE, stdin);
        if(!strcmp(buf, "q\n") || !strcmp(buf, "Q\n"))
        {
            shutdown(sock, SHUT_WR);
            return;
        }
        write(sock, buf, strlen(buf));
    }
}

void error_handling(char* message)
{
    fputs(message, stderr);
    fputc('\n', stderr);
    exit(-1);
}
